JP3632424B2 - Control device for valve opening / closing characteristics of internal combustion engine - Google Patents

Control device for valve opening / closing characteristics of internal combustion engine Download PDF

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Publication number
JP3632424B2
JP3632424B2 JP01896398A JP1896398A JP3632424B2 JP 3632424 B2 JP3632424 B2 JP 3632424B2 JP 01896398 A JP01896398 A JP 01896398A JP 1896398 A JP1896398 A JP 1896398A JP 3632424 B2 JP3632424 B2 JP 3632424B2
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valve
fuel
valve opening
advance
engine
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JP01896398A
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JPH11210509A (en
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保 荻田
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Toyota Motor Corp
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Toyota Motor Corp
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Priority to US09/225,744 priority patent/US6109225A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0203—Variable control of intake and exhaust valves
    • F02D13/0215—Variable control of intake and exhaust valves changing the valve timing only
    • F02D13/0219—Variable control of intake and exhaust valves changing the valve timing only by shifting the phase, i.e. the opening periods of the valves are constant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
    • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
    • F01L1/34403—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear using helically teethed sleeve or gear moving axially between crankshaft and camshaft
    • F01L1/34406—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear using helically teethed sleeve or gear moving axially between crankshaft and camshaft the helically teethed sleeve being located in the camshaft driving pulley
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0261—Controlling the valve overlap
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D41/0047—Controlling exhaust gas recirculation [EGR]
    • F02D41/006—Controlling exhaust gas recirculation [EGR] using internal EGR
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L2201/00—Electronic control systems; Apparatus or methods therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B1/00—Engines characterised by fuel-air mixture compression
    • F02B1/02—Engines characterised by fuel-air mixture compression with positive ignition
    • F02B1/04—Engines characterised by fuel-air mixture compression with positive ignition with fuel-air mixture admission into cylinder
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/02—Engines characterised by their cycles, e.g. six-stroke
    • F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
    • F02B2075/027—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle four
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
    • F02B75/18—Multi-cylinder engines
    • F02B2075/1804—Number of cylinders
    • F02B2075/1816—Number of cylinders four
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
    • F02B2275/18—DOHC [Double overhead camshaft]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
    • F02B75/18—Multi-cylinder engines
    • F02B75/20—Multi-cylinder engines with cylinders all in one line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D2013/0292—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation in the start-up phase, e.g. for warming-up cold engine or catalyst
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0002—Controlling intake air
    • F02D2041/001—Controlling intake air for engines with variable valve actuation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/06—Fuel or fuel supply system parameters
    • F02D2200/0611—Fuel type, fuel composition or fuel quality
    • F02D2200/0612—Fuel type, fuel composition or fuel quality determined by estimation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M25/00—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture
    • F02M25/08—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding fuel vapours drawn from engine fuel reservoir
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は内燃機関のバルブ開閉特性制御装置に関し、特に、性状が異なる燃料が供給された場合でも、バルブ開閉特性を補正することにより、内燃機関の燃費を悪化させることなく、かつ、排気エミッションを低減することができる内燃機関のバルブ開閉特性制御装置に関する。
【０００２】
【従来の技術】
従来、内燃機関のシリンダヘッドに設けられた吸気弁、及び排気弁の開閉タイミングは、クランク軸の回転位相に一義的に同期しているので、燃焼室における吸排気量は、吸気通路に設けられたスロットル弁の開度や機関の回転速度に依存することになる。
【０００３】
これに対して、近年、燃焼室における吸排気量を更に自由度をもって調節可能とするために、吸気弁と排気弁（以後、吸排気弁という）の開閉タイミングを変更できるようにした装置（可変バルブタイミング機構：ＶＶＴ）が実用化されている。この可変バルブタイミング機構は、吸排気弁の開閉タイミングを変更可能とする機械的な可変機構と、この可変機構の動きを制御するためのコンピュータを用いた制御装置とから構成されている。制御装置は機関の運転状態に応じて可変機構を制御することにより、吸気弁又は排気弁の少なくとも一方の開閉タイミングを制御し、吸気弁と排気弁が同時に開いている期間の長さ（バルブオーバラップ量の大きさ）を制御する。この制御により、燃焼室に吸入される空気量、或いは、燃焼室から一旦排出された排気ガスが燃焼室に逆流して残留する量、即ち、内部ＥＧＲ量が適正化され、機関の出力、エミッションや、燃費等の改善が図られる。
【０００４】
そして、可変バルブタイミング機構の中には、吸排気弁の開閉タイミングを連続的に変更可能とする可変機構を備えたものがある。このような連続可変式の可変バルブタイミング機構では、コンピュータによって機関の運転状態が検出されて吸排気弁の目標開閉タイミングが算出されると共に、吸排気弁の実際の開閉タイミングが検出され、両者が一致するように可変機構がフィードバック制御される。
【０００５】
一方、このような連続可変式の可変バルブタイミング機構において、可変機構に所期の動作が得られなくなるような異常が発生した場合には、機関に種々の不具合が発生することになる。例えば、機関負荷が小さい時にバルブオーバラップ量が大きくなった状態で可変機構が動作しなくなった場合には、機関がストールする恐れがある。そして、一旦、ストールが発生すると、その後に可変機構の異常を検出することができない。
【０００６】
そこで、連続可変式の可変バルブタイミング機構において、機関のストールの発生を判断条件として制御装置の異常を検出することにより、ストールにより機関が停止した後でも可変機構の異常を検出できるようにした、内燃機関のバルブタイミング制御装置のための異常検出装置を本出願人は既に提案した（特開平９−６０５３５号公報参照）。
【０００７】
この特開平９−６０５３５号公報に記載の連続可変式の可変バルブタイミング機構には、バルブオーバラップ量を大きくすると内部ＥＧＲの増加によりＮＯｘの低減効果があり、ポンピングロスによる燃費の向上効果が得られることが開示されている。
ところで、内燃機関に使用される燃料の成分は使用条件に係わらず一定にはなっておらず、その燃料が主に使用される場所の温度に応じて揮発度が同じになるように、何種類かの性状に別れている。このような燃料の性状は大別すると以下の３種類になる。
【０００８】
軽質燃料：低沸点分が多い燃料
重質燃料：低沸点分が少ない燃料
中質燃料：低沸点分が軽質燃料と重質燃料の中間の燃料
【０００９】
【発明が解決しようとする課題】
しかしながら、特開平９−６０５３５号公報に記載の連続可変式の可変バルブタイミング機構には、前述のような燃料性状に対する考慮がされておらず、燃料性状に応じた制御はされていないので、例えば、重質燃料が使用された場合には燃料の壁面付着量が多くなり、この付着量は不安定であるので燃焼が不安定となる場合があるという問題点があった。
【００１０】
そこで、本発明は、連続可変式の可変バルブタイミング機構において、燃料の性状を考慮してバルブオーバラップ量を制御することにより、燃料性状にかかわらず、ＮＯｘの低減効果があり、ポンピングロスによる燃費の向上効果が得られる内燃機関のバルブ開閉特性制御装置を提供することを目的としている。
【００１１】
【課題を解決するための手段】
請求項１に記載の発明によれば、１つの気筒の吸気弁の開弁から排気弁の閉弁までのバルブオーバラップ量を変更可能なバルブ可変手段を備え、機関の運転状態に応じてこのバルブ可変手段の作動量を制御する制御手段を有する内燃機関のバルブ開閉特性制御装置において、内燃機関で燃焼される燃料の性状を検出する燃料性状検出手段と、この燃料性状検出手段によって検出された燃料性状に応じて、前記制御手段の制御速度を補正する制御手段の作動速度補正手段と、を設けたことを特徴とする内燃機関のバルブ開閉特性制御装置が提供される。
【００１２】
請求項２に記載の発明によれば、請求項１に記載の内燃機関のバルブ開閉特性制御装置において、前記制御手段は、機関温度が所定値以上の時に、前記バルブ可変手段を作動させることを特徴とする内燃機関のバルブ開閉特性制御装置が提供される。
【００１３】
すなわち、請求項１の発明では燃料性状に応じて、バルブ可変手段の作動量を制御する制御手段の作動速度が変更されるため、燃料の壁面付着量の変化量を制御することが可能となり、燃焼を安定させることができる。
【００１４】
すなわち、請求項２の発明では、燃料の壁面付着量が機関温度により変化することを考慮してバルブ可変手段を作動させるようにしたため、更に最適な制御を達成することができる。
【００１６】
【発明の実施の形態】
以下添付図面を用いて本発明の実施形態を具体的な実施例に基づいて詳細に説明する。
図１は本発明のバルブ開閉特性制御装置１０を備えた電子燃料噴射制御式の多気筒内燃機関１１の全体構成を示すものである。内燃機関１１は４気筒４サイクル火花点火式内燃機関であり、マイクロコンピュータを内蔵したＥＣＵ（エンジン・コントロール・ユニット）２１によって制御される。
【００１７】
エアクリーナ２２の下流側にはスロットル弁１２とサージタンク２３がこの順に設けられている。エアクリーナ２２の近傍には吸気温を検出する吸気温センサ２４が取り付けられており、また、スロットル弁１２にはスロットル弁１２が全閉状態でオンとなるアイドルスイッチ２５が取り付けられている。更に、サージタンク２３にはダイヤフラム式の圧力センサ２６が設けられている。一方、スロットル弁１２を迂回し、かつ、スロットル弁１２の上流側と下流側とを連通するバイパス通路１３が設けられており、そのバイパス通路１３の途中にはソレノイドによって開度が制御されるＩＳＣＶ（アイドル・スピード・コントロール・バルブ）１４が設けられている。このＩＳＣＶ１４に流れる電流はデューティ制御されてＩＳＣＶ１４の開度が調節され、この結果、バイパス通路１３を流れる空気量が調節されてアイドリング回転数が目標回転数に制御される。
【００１８】
サージタンク２３は吸気マニホルド２７及び吸気ポート２８を通じて機関１１の燃焼室３０に連通している。サージタンク２３の下流側には、圧力センサ２６により検出された吸入空気量に応じた加圧燃料１８を、各気筒毎に燃料供給系から吸気ポートへ供給するための燃料噴射弁１９が設けられている。アイドルスイッチ２５の出力と圧力センサ２６の出力はＥＣＵ２１に入力される。
【００１９】
燃焼室３０から排出された排気ガスは、排気ポート３１及び排気マニホルド３２を介して触媒装置３３に導かれ、浄化されて大気中に排出される。この触媒装置３３の上流側の排気マニホルド３２には、空燃比センサの一種である酸素センサ４１が設けられている。酸素センサ４１は排気ガス中の酸素成分濃度に応じて電気信号を発生する。酸素センサ４１の出力はＥＣＵ２１に入力される。
【００２０】
吸気ポート２８は吸気弁９によって開閉され、排気ポート３１は排気弁８によって開閉される。排気弁８及び吸気弁９の開閉時期は、バルブ開閉特性制御装置１０によって制御される。この実施例のバルブ開閉特性制御装置１０は、排気弁８の閉弁時期の遅角制御、及び吸気弁９の開弁時期の進角制御を行うことができ、排気弁８が閉じる前に吸気弁９が開いて両者が同時に開いている期間（バルブオーバラップ量）を制御することができる。バルブ開閉特性制御装置１０はＥＣＵ２１により制御される。このバルブ開閉特性制御装置１０の構成は本出願人が既に出願した特開平９−６０５３５号公報に記載のものと同じであるので、ここではその説明を省略する。
【００２１】
また、３４は燃焼室３０内に火花を発生させる点火プラグであり、３５は燃焼室３０内を往復動するピストンである。イグナイタ３６は高電圧を発生し、この高電圧がディストリビュータ３７により各気筒の点火プラグ３４に分配供給される。回転角センサ３８はディストリビュータ３７の回転軸の回転を検出するものであり、例えば、３０°ＣＡ毎に機関の回転信号が回転角センサ３８からＥＣＵ２１に送られる。
【００２２】
また、内燃機関１１のシリンダブロック４０内には、冷却水の温度を検出するための水温センサ３９が設けられている。水温センサ３９は冷却水の温度に応じたアナログ電圧の電気信号を発生し、水温センサ信号（ＴＨＷ）がＥＣＵ２１に送られる。
燃料タンク１７の下部には燃料温センサ４２が設けられており、これにより燃料１８の温度が測定される。燃料タンク１７の上部にはベーパ通路４３が形成されており、そのベーパ通路４３はベーパ流量計４４を介してキャニスタ４５に連通されている。燃料タンク１７で発生したベーパは、ベーパ流量計４４によりその流量が測定された後、キャニスタ４５に流れ込む。ベーパ流量計４４はベーパの流量に応動して回転する回転部４６を備えており、この回転部４６の回転がベーパ流量センサ４７で検出され、検出されたベーパ流量の検出信号がＥＣＵ２１に入力される。
【００２３】
このベーパ流量センサ４７によって検出されたベーパ流量の検出信号により、燃料タンク１７内の燃料１８の蒸発のしにくさ（蒸留特性）により、ＥＣＵ２１は燃料タンク１７内の燃料１８の性状、即ち、燃料が軽質燃料か重質燃料、或いは中質燃料かを検出することができる。
そして、キャニスタ４５に吸着されたベーパは、パージ通路４８を介して吸気マニホルド２７に吸入される。パージ通路４８には図示しないオリフィスが設けられているため、吸気マニホルド２７の負圧が燃料タンク１７に直接かかることはない。このパージ通路４８の途中にはパージコントロール弁４９が設けられており、このパージコントロール弁４９のソレノイドに流れる電流を調整することによりパージコントロール弁４９の開度が調整され、パージ通路４８を流れるパージ流量が調節される。
【００２４】
マイクロコンピュータを内蔵するＥＣＵ２１は、図２に示すような構成を備えている。図中、図１と同じ構成部分には同じ符号を付してその説明を省略する。図２において、ＥＣＵ２１はＭＰＵ（マイクロ・プロセッサ・ユニット）５１、処理プログラムを内蔵したＲＯＭ５２、作業領域として使用されるＲＡＭ５３、機関停止後もデータを保持するバックアップＲＡＭ５４、ＭＰＵ５１へクロック信号を供給するクロック発生器５５を備え、これらは双方向のバスライン５６によって相互に接続されている。このバスライン５６には入出力ポート５７、入力ポート５７、及び出力ポート５９が接続されている。
【００２５】
入出力ポート５７にはマルチプレクサ６８とＡ／Ｄ変換器６９を介して４つのバッファ６４〜６７が接続されている。バッファ６４には圧力センサ２６の検出信号がフィルタ６３を介して入力されるが、バッファ６５〜６７には吸気温センサ２４、水温センサ６５、及び燃料温センサ４２からの検出信号がそれぞれ入力される。フィルタ６３は圧力センサ２６の検出信号中に含まれる吸気管圧力の振動成分を除去するものである。また、マルチプレクサ６８は入力された信号を選択出力するものである。
【００２６】
入力ポート５８には、酸素センサ４１の検出信号がバッファ７０とコンパレータ７１を介して入力されると共に、回転角センサ３８とベーパ流量センサ４７の検出出力が波形整形回路７２を介して入力される。入力ポート５８には更に、アイドル信号２５からのオンオフ信号も入力される。
出力ポート５９には駆動回路７３〜７７がそれぞれ接続されている。駆動回路７３はイグナイタ３６を駆動し、駆動回路７４は燃料噴射弁１９を駆動し、駆動回路７５はＩＳＣＶ１４を駆動し、駆動回路７６はパージコントロール弁４９を駆動し、駆動回路７７はバルブ開閉特性制御装置１０を駆動する。
【００２７】
以上のように構成されたＥＣＵ２１は、ベーパ流量センサ４７により、燃料１８の性状を検出することができる。その検出の一例を図３に示すフローチャートにより説明する。
図３（ａ） は燃料性状判定係数ＮＶＡ１０Ｔの算出手順を示すものであり、メインルーチンの一部である。ステップ３０１では、流量計計測時間ＣＶＡが図示しない４ｍｓルーチンでカウントアップされ、所定値、例えば１０秒以上になったか否かを判定し、１０秒以内の時はこのルーチンを終了し、１０秒経過した時は次のステップ３０２に進む。ステップ３０２では流量計の計測時間ＣＶＡが０にリセットされる。従って、ステップ３０２〜ステップ３０６は１０秒に１回の割合で処理が実行される。
【００２８】
一方、ＥＣＵ２１は前述したベーパ流量センサ４７の検出信号が低電圧から高電圧に変化した時のみ、即ち、図２の回転部４６が１回転する毎に、起動される外部割り込みルーチンでカウントアップされるベーパ流量カウンタを有する。そして、ベーパ量カウンタのカウント値ＮＶＡがステップ３０２の次のステップ３０３で変数ＮＶＡ１０にセットされる。このベーパ量カウンタのカウント値ＮＶＡは、次のステップ３０４で０にリセットされる。従って、変数ＮＶＡ１０の値は１０秒間当たりのベーパ流量計４４の回転部４６の回転数を示すことになり、ベーパ流量に比例した値を示すことになる。
【００２９】
続くステップ３０５では、燃料温センサ４２により燃料１８の温度が検出され、得られた燃料温度検出信号ＴＨＦに基づいて、燃料温補正係数ＫＶＡが関数ｆ（ＴＨＦ）を用いて算出される。即ち、蒸留特性が同一の燃料であっても、燃料温度が低い時はベーパ発生量は高温の時よりも少なくなる。このため、燃料温度によるベーパ発生量の違いを補正すべく、燃料温度が低くなるほど燃料温補正係数ＫＶＡの値が大きくなるように設定されている。
【００３０】
次のステップ３０６では、燃料性状補正係数ＮＶＡ１０ＴがＮＶＡ１０×ＫＶＡなる演算式により求められる。即ち、この燃料性状補正係数ＮＶＡ１０Ｔは、１０秒間のベーパ流量を燃料温補正係数で補正した値であるため、この値が大きい時は高沸点分が少ない（低沸点分が多い）軽質燃料であり、この値が小さい時は高沸点分の多い（低沸点分が少ない）重質燃料であることがわかる。この燃料性状補正係数ＮＶＡ１０Ｔの値の大きさと燃料性状との関係を図示すると、図３（ｂ） のようになる。
【００３１】
ステップ３０７ではこの燃料性状補正係数ＮＶＡ１０Ｔの値の大きさが所定値α以上か否かを判定し、ＮＶＡ１０Ｔ≧αの場合はステップ３０８に進み、燃料を軽質燃料と判定してこのルーチンを終了する。一方、ステップ３０７でＮＶＡ１０Ｔ＜αの場合はステップ３０９に進み、燃料性状補正係数ＮＶＡ１０Ｔの値の大きさが所定値αよりも小さな所定値β以下か否かを判定する。そして、ステップ３０９においてＮＶＡ１０Ｔ≦βの場合はステップ３１１に進み、燃料を重質燃料と判定してこのルーチンを終了する。一方、ステップ３０９でＮＶＡ１０Ｔ＞βの場合はステップ３１１に進み、燃料を中質燃料と判定してこのルーチンを終了する。
【００３２】
なお、この燃料性状の判定は、連続可変式の可変バルブタイミング機構を搭載した内燃機関の場合、冷間始動時のように、可変バルブタイミング機構を作動させない間に行い、検出した燃料性状をＲＡＭ５３、或いはバックアップＲＡＭ５４に保持しておけば良い。一方、この実施例ではベーパ流量の単位計測時間を１０秒としているので、車両の走行中であっても逐次燃料性状を検出することができ、車両が走行の途中で給油を行い、異なる性状の燃料が供給された場合でも、燃料性状の変化を検出することができる。
【００３３】
ここで、以上のような手順により燃料の性状を判定することができる内燃機関に備えられた連続可変式の可変バルブタイミング機構の、吸気弁の開弁時期の進角制御、及び、排気弁の閉弁時期の遅角制御について説明する。
図４は、内燃機関のバルブ開閉特性制御装置１０における吸気弁９の開弁時期を進角制御する手順の第１の実施例を示すフローチャートである。ステップ４００では図３（ａ） で説明した手順によって求められた燃料の性状の読み込みを行う。そして、続くステップ４０１で燃料が軽質燃料か否かを判定する。
【００３４】
燃料が軽質燃料の場合はステップ４０２に進み、吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ４０３に進み、吸気弁９の開弁進角制御量をＸ°ＣＡに設定してこのルーチンを終了する。一方、ステップ４０１で軽質燃料でない場合はステップ４０４に進み、燃料が重質燃料か否かを判定する。
【００３５】
燃料が重質燃料でない場合は、燃料が中質燃料であるのでステップ４０５に進み、吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ４０３に進み、吸気弁９の開弁進角制御量をＹ°ＣＡに設定してこのルーチンを終了する。この時設定される吸気弁９の開弁進角制御量Ｙ°ＣＡは、燃料が軽質の時の開弁進角制御量Ｘ°ＣＡよりも小さな値である。一方、ステップ４０４で重質燃料と判定した場合はステップ４０７に進む。
【００３６】
燃料が重質燃料の場合はステップ４０７において吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ４０８に進み、吸気弁９の開弁進角制御量をＺ°ＣＡに設定してこのルーチンを終了する。燃料が重質燃料の時に設定される吸気弁９の開弁進角制御量Ｚ°ＣＡは、燃料が中質の時の開弁進角制御量Ｙ°ＣＡよりも小さな値である。
【００３７】
ここで、内燃機関の吸気行程における或る気筒の排気弁８と吸気弁９の開弁期間の重なりであるバルブオーバラップについて図１２（ａ） を用いて説明する。図１２（ａ） に実線ＥＶで示される特性が排気弁８の開弁特性であり、実線ＩＶで示される特性が吸気弁９の開弁特性であり、この場合は排気弁８と吸気弁９の開弁期間が重なっておらず、バルブオーバラップ量は０である。この状態から吸気弁９の開弁進角条件の場合に、吸気弁９の開弁特性を進角させると、吸気弁９の開弁時期は図１２（ａ） に破線で示すように早まり、排気弁８の開弁特性と吸気弁９の開弁特性が重なる。この排気弁８の開弁特性と吸気弁９の開弁特性の重なりがバルブオーバラップ量である。オーバラップ量は、吸気弁９の開弁進角制御量が大きい程大きくなる。
【００３８】
従来のバルブ開閉特性制御装置では、機関の運転状態に応じて吸気弁９の開弁進角制御量が変更されていたが、その制御量は燃料性状に係わらず、機関の或る運転状態では一定であった。一般に、バルブ開閉特性制御装置を備えた内燃機関では、バルブオーバラップ量を大きくすると内部ＥＧＲ量が増加する。このため、壁面付着量の多い重質燃料が使用された場合には燃焼不安定となり、ドライバビリティが悪化していた。
【００３９】
これを防止するために、前述の第１の実施例では、図４で説明した手順により、燃料に重質燃料や中質燃料が使用された場合には、吸気弁９の開弁進角制御量を、燃料に軽質燃料が使用された場合に比べて小さくしている。この結果、吸気弁９の開弁進角条件の場合には、バルブオーバラップ量が燃料の性状に応じて変更されるので、ドライバビリティの悪化が防止されることになる。
【００４０】
図５は、内燃機関のバルブ開閉特性制御装置１０の排気弁８の閉弁時期を遅角制御する手順の第１の実施例を示すフローチャートである。排気弁８の閉弁時期の制御手順の説明においては、図４で説明した吸気弁９の開弁時期の制御手順と同じ手順については同じステップ番号を付して説明する。
排気弁８の閉弁時期の遅角制御においても、燃料の性状を判定するステップ４００、４０１、及び４０４の手順は同じである。そして、ステップ４０１で燃料が軽質燃料と判定した場合はステップ５０１に進み、排気弁８が閉弁遅角条件か否かを判定する。そして、排気弁８の閉弁遅角条件でない時にはこのままこのルーチンを終了するが、排気弁８の閉弁遅角条件の場合はステップ５０２に進み、排気弁８の閉弁遅角制御量をＰ°ＣＡに設定してこのルーチンを終了する。
【００４１】
一方、ステップ４０４で燃料が中質燃料と判定された場合はステップ５０３に進み、排気弁８が閉弁遅角条件か否かを判定する。そして、排気弁８の閉弁遅角条件でない時にはこのままこのルーチンを終了するが、排気弁８の閉弁遅角条件の場合はステップ５０４に進み、排気弁８の閉弁遅角制御量をＱ°ＣＡに設定してこのルーチンを終了する。この時に設定される排気弁８の閉弁遅角制御量Ｑ°ＣＡは、燃料が軽質の時の閉弁遅角制御量Ｐ°ＣＡよりも小さな値である。
【００４２】
一方、ステップ４０４で重質燃料と判定した場合はステップ５０５に進む。ステップ５０５では排気弁８が閉弁遅角条件か否かを判定する。そして、排気弁８の閉弁遅角条件でない時にはこのままこのルーチンを終了するが、排気弁８の閉弁遅角条件の場合はステップ５０６に進み、排気弁８の閉弁遅角制御量をＲ°ＣＡに設定してこのルーチンを終了する。燃料が重質燃料の時に設定される吸気弁９の閉弁遅角制御量Ｒ°ＣＡは、燃料が中質の時の閉弁遅角制御量Ｑ°ＣＡよりも小さな値である。
【００４３】
このように、第１の実施例では、排気弁８の閉弁遅角制御量についても、燃料の性状に応じた調整がなされる。これを図１２（ｂ） を用いて説明するが、図１２（ｂ） においても実線ＥＶで示される特性が排気弁８の開弁特性であり、実線ＩＶで示される特性が吸気弁９の開弁特性である。排気弁８についても、排気弁８の閉弁を遅らせると、排気弁８の開弁特性は図１２（ｂ） に破線で示すようになり、排気弁８と吸気弁９のバルブオーバラップ量が大きくなる。
【００４４】
第１の実施例では、図５で説明した手順により、排気弁８の閉弁遅角条件の時にも、燃料に重質燃料や中質燃料が使用された場合には、排気弁８の閉弁遅角制御量を、燃料に軽質燃料が使用された場合に比べて小さくしている。この結果、排気弁８の閉弁遅角条件の場合には、バルブオーバラップ量が燃料の性状に応じて、同じ開弁進角条件では重質燃料になるほど小さくなるように変更されるので、ドライバビリティの悪化が防止されることになる。
【００４５】
このように、吸気弁９の開弁進角制御量と、排気弁８の閉弁遅角制御量とは、ほぼ同様の制御により、燃料性状に応じて変更することができる。よって、以後の説明では、燃料の性状を考慮した吸気弁９の開弁進角制御の実施例についてのみ説明し、排気弁８の閉弁遅角制御の実施例についてはその説明を省略する。
図６は、内燃機関のバルブ開閉特性制御装置１０における吸気弁９の開弁時期を進角制御する手順の第２の実施例を示すフローチャートである。第２の実施例の制御手順の説明においては、図４で説明した第１の実施例の吸気弁９の開弁時期の制御手順と同じ手順については同じステップ番号を付して説明する。
【００４６】
ステップ６００では図３（ａ） で説明した手順によって求められた燃料の性状の読み込み、及び、機関の負荷と回転数の読み込みを行う。そして、続くステップ４０１とステップ４０４において燃料の性状が軽質燃料、中質燃料、或いは重質燃料のいずれであるかを判定する。
燃料が軽質燃料の場合はステップ４０２において吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ６０１に進む。ステップ６０１では、吸気弁９の開弁進角量を、ＥＣＵ２１のＲＯＭ５２に記憶された軟質燃料の進角マップＡを読み込んでこのルーチンを終了する。マップＡは図７（ａ） に示すように、機関回転数と機関負荷の大きさに応じた吸気弁９の開弁進角特性を与えるものである。
【００４７】
また、燃料が中質燃料の場合はステップ４０５において吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ６０２に進む。ステップ６０２では、吸気弁９の開弁進角量を、ＥＣＵ２１のＲＯＭ５２に記憶された中質燃料の進角マップＢから読み込んでこのルーチンを終了する。マップＢは図７（ｂ） に実線で示す特性を備えており、機関回転数と機関負荷の大きさに応じた吸気弁９の開弁進角特性を与えるものである。なお、比較のために、マップＢには軽質燃料の開弁進角特性を点線で示してあり、重質燃料の開弁進角特性を二点鎖線で示してある。
【００４８】
更に、燃料が重質燃料の場合はステップ４０７において吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ６０３に進む。ステップ６０３では、吸気弁９の開弁進角量を、ＥＣＵ２１のＲＯＭ５２に記憶された重質燃料の進角マップＣから読み込んでこのルーチンを終了する。マップＣは図７（ｃ） に実線で示す特性を備えており、機関回転数と機関負荷の大きさに応じた吸気弁９の開弁進角特性を与えるものである。なお、比較のために、マップＣには軽質燃料の開弁進角特性が点線で示してある。
【００４９】
第２の実施例では、図６で説明した手順により、燃料に重質燃料や中質燃料が使用された場合には、吸気弁９の同じ開弁進角値を与える機関回転数と機関負荷の値が大きくなっている。この結果、吸気弁９の開弁進角条件の場合には、バルブオーバラップ量が燃料の性状に応じて、同じ開弁進角条件では重質燃料になるほど小さくなるように変更されるので、ドライバビリティの悪化が防止されることになる。
【００５０】
図８は、内燃機関のバルブ開閉特性制御装置１０における吸気弁９の開弁時期を進角制御する手順の第３の実施例を示すフローチャートである。第３の実施例の制御手順の説明においては、図４で説明した第１の実施例の吸気弁９の開弁時期の制御手順と同じ手順については同じステップ番号を付して説明する。
ステップ４００では図３（ａ） で説明した手順によって求められた燃料の性状の読み込みを行う。そして、続くステップ４０１とステップ４０４において燃料の性状が軽質燃料、中質燃料、或いは重質燃料のいずれであるかを判定する。
【００５１】
燃料が軽質燃料の場合はステップ４０２において吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ８０１に進む。ステップ８０１では、吸気弁９の開弁進角速度をＦｄｅｇ／ｍｓに設定してこのルーチンを終了する。
【００５２】
また、燃料が中質燃料の場合はステップ４０５において吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ８０２に進む。ステップ８０２では、吸気弁９の開弁進角速度をＭｄｅｇ／ｍｓに設定してこのルーチンを終了する。この時の開弁進角速度をＭｄｅｇ／ｍｓは、燃料が軽質燃料の時の吸気弁９の開弁進角速度Ｆｄｅｇ／ｍｓよりも小さな値である。
【００５３】
更に、燃料が重質燃料の場合はステップ４０７において吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ８０３に進む。ステップ８０３では、吸気弁９の開弁進角速度をＳｄｅｇ／ｍｓに設定してこのルーチンを終了する。この時の開弁進角速度をＳｄｅｇ／ｍｓは、燃料が中質燃料の時の吸気弁９の開弁進角速度Ｍｄｅｇ／ｍｓよりも小さな値である。
【００５４】
バルブ開閉特性制御装置１０における吸気弁９の進角速度の制御は、バルブ開閉特性制御装置１０に設けられた進角室と遅角室に印加される油圧を、オイル制御弁をデューティ制御することによって行うことができる。即ち、デューティ比を大きくして進角室に印加される油圧を大きくすれば、進角速度を増大させることができる。
【００５５】
第３の実施例では、図８で説明した手順により、燃料に重質燃料や中質燃料が使用された場合には、吸気弁９の同じ開弁進角速度が、軽質燃料よりも中質燃料が小さく、また、中質燃料よりも重質燃料が小さくなっている。この結果、吸気弁９の開弁進角条件の場合には、バルブオーバラップ量が燃料の性状に応じて、同じ開弁進角条件では重質燃料になるほど小さくなるように変更されるので、ドライバビリティの悪化が防止されることになる。
【００５６】
図９は、内燃機関のバルブ開閉特性制御装置１０における吸気弁９の開弁時期を進角制御する手順の第４の実施例を示すフローチャートである。第４の実施例の制御手順の説明においては、図４で説明した第１の実施例の吸気弁９の開弁時期の制御手順と同じ手順については同じステップ番号を付して説明する。
ステップ９００では図３（ａ） で説明した手順によって求められた燃料の性状の読み込みと、機関水温の読み込みを行う。そして、続くステップ４０１とステップ４０４において燃料の性状が軽質燃料、中質燃料、或いは重質燃料のいずれであるかを判定する。
【００５７】
燃料が軽質燃料の場合はステップ４０２において吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ９０１に進む。ステップ９０１では、機関の水温がＬ℃以上か否かを判定する。そして、機関の水温＜Ｌ℃の時にはこのままこのルーチンを終了するが、機関の水温≧Ｌ℃の時にはステップ９０２に進む。ステップ９０２では、軟質燃料に応じた吸気弁の開弁進角制御を実行してこのルーチンを終了する。この軟質燃料に応じた吸気弁の開弁進角制御は、第１の実施例で説明した進角制御量Ｘ、第２の実施例で説明した進角マップＡによる進角値、或いは、第３の実施例で説明した進角速度Ｆｄｅｇ／ｍｓのいずれか１つを実行することができる。
【００５８】
また、燃料が中質燃料の場合はステップ４０５において吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ９０３に進む。ステップ９０３では、機関の水温がＩ℃以上か否かを判定する。この機関水温Ｉはステップ９０１における機関水温Ｌよりも高い値である。そして、機関の水温＜Ｉ℃の時にはこのままこのルーチンを終了するが、機関の水温≧Ｉ℃の時にはステップ９０４に進む。ステップ９０４では、中質燃料に応じた吸気弁の開弁進角制御を実行してこのルーチンを終了する。この中質燃料に応じた吸気弁の開弁進角制御は、ステップ９０２における進角制御が、第１の実施例で説明した進角制御量Ｘである時は進角制御量Ｙ、第２の実施例で説明した進角マップＡによる進角値である時は進角マップＢによる進角値、及び、第３の実施例で説明した進角速度Ｆｄｅｇ／ｍｓである時は進角速度Ｍｄｅｇ／ｍｓである。
【００５９】
更に、燃料が重質燃料の場合はステップ４０７において吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ９０５に進む。ステップ９０５では、機関の水温がＨ℃以上か否かを判定する。この機関水温Ｈはステップ９０３における機関水温Ｉよりも低い値である。そして、機関の水温＜Ｈ℃の時にはこのままこのルーチンを終了するが、機関の水温≧Ｈ℃の時にはステップ９０６に進む。ステップ９０６では、重質燃料に応じた吸気弁の開弁進角制御を実行してこのルーチンを終了する。この重質燃料に応じた吸気弁の開弁進角制御は、ステップ９０２における進角制御が、第１の実施例で説明した進角制御量Ｘである時は進角制御量Ｚ、第２の実施例で説明した進角マップＡによる進角値である時は進角マップＣによる進角値、及び、第３の実施例で説明した進角速度Ｆｄｅｇ／ｍｓである時は進角速度Ｓｄｅｇ／ｍｓである。
【００６０】
第４の実施例は、図９で説明した手順から分かるように、第１から第３の実施例で説明した手順に機関水温の判定が加わったものである。そして、燃料に重質燃料や中質燃料が使用された場合には、吸気弁９の開弁進角を実行するか否かを判定する水温値が、軽質燃料よりも中質燃料の方が高く、また、中質燃料よりも重質燃料の方が高くされている。この結果、吸気弁９の開弁進角条件の判定に、機関の暖機状態が加わることになり、一層確実にドライバビリティの悪化が防止されると共に、燃費が向上し、排気エミッションの最適化が図れる。
【００６１】
図１０は、内燃機関のバルブ開閉特性制御装置１０における吸気弁９の開弁時期を進角制御する手順の第５の実施例を示すフローチャートである。第５の実施例の制御手順の説明においては、図４で説明した第１の実施例の吸気弁９の開弁時期の制御手順と同じ手順については同じステップ番号を付して説明する。
ステップ１０００では図３（ａ） で説明した手順によって求められた燃料の性状の読み込み、機関水温の読み込み、機関負荷の読み込み、及び、機関回転数の読み込みを行う。そして、続くステップ４０１とステップ４０４において燃料の性状が軽質燃料、中質燃料、或いは重質燃料のいずれであるかを判定する。
【００６２】
燃料が軽質燃料の場合はステップ４０２において吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ９０１に進む。ステップ９０１では、機関の水温がＬ℃以上か否かを判定する。そして、機関の水温≧Ｌ℃の時にはステップ６０１の処理を実行した後にこのルーチンを終了し、機関の水温＜Ｌ℃の時にはステップ１００１の処理を実行した後にこのルーチンを終了する。
【００６３】
ステップ６０１は第２の実施例の処理と同じであり、吸気弁９の開弁進角量を、ＥＣＵ２１のＲＯＭ５２に記憶された軟質燃料の進角マップＡから読み込む。マップＡは図７（ａ） で説明したように、機関回転数と機関負荷の大きさに応じた吸気弁９の開弁進角特性を与えるものである。一方、ステップ１００１では、吸気弁９の開弁進角量を、ＥＣＵ２１のＲＯＭ５２に記憶された軟質燃料の進角マップＤから読み込む。マップＤは機関水温が低い時の軟質燃料用の進角マップであり、その特性は図１１（ａ） に示される。マップＤもマップＡと同様に、機関回転数と機関負荷の大きさに応じた吸気弁９の開弁進角特性を与えるものであるが、図７（ａ） に示されるマップＡと比べると分かるように、機関回転数と機関負荷の大きさに応じた吸気弁９の開弁進角値は、機関水温が高い時に比べて小さくなっている。
【００６４】
また、燃料が中質燃料の場合はステップ４０５において吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ９０３に進む。ステップ９０３では、機関の水温がＩ℃以上か否かを判定する。この機関水温Ｉはステップ９０１における機関水温Ｌよりも高い値である。そして、機関の水温≧Ｉ℃の時にはステップ６０２の処理を実行した後にこのルーチンを終了し、機関の水温＜Ｉ℃の時にはステップ１００２の処理を実行した後にこのルーチンを終了する。
【００６５】
ステップ６０２は第２の実施例の処理と同じであり、吸気弁９の開弁進角量を、ＥＣＵ２１のＲＯＭ５２に記憶された中質燃料の進角マップＢから読み込む。マップＢは図７（ｂ） で説明したように、機関回転数と機関負荷の大きさに応じた吸気弁９の開弁進角特性を与えるものである。一方、ステップ１００２では、吸気弁９の開弁進角量を、ＥＣＵ２１のＲＯＭ５２に記憶された中質燃料の進角マップＥから読み込む。マップＥは機関水温が低い時の中質燃料用の進角マップであり、その特性は図１１（ｂ） に実線で示される。マップＥもマップＢと同様に、機関回転数と機関負荷の大きさに応じた吸気弁９の開弁進角特性を与えるものであるが、図７（ｂ） に示されるマップＢと比べると分かるように、機関回転数と機関負荷の大きさに応じた吸気弁９の開弁進角値は、機関水温が高い時に比べて小さくなっている。なお、比較のために、マップＥには軽質燃料の機関低温時の開弁進角特性を点線で示してあり、重質燃料の機関低温時の開弁進角特性を二点鎖線で示してある。
【００６６】
更に、燃料が重質燃料の場合はステップ４０７において吸気弁９が開弁進角条件か否かを判定する。そして、吸気弁９の開弁進角条件でない時にはこのままこのルーチンを終了するが、吸気弁９の開弁進角条件の場合はステップ９０５に進む。ステップ９０５では、機関の水温がＨ℃以上か否かを判定する。この機関水温Ｈはステップ９０３における機関水温Ｉよりも低い値である。そして、機関の水温≧Ｈ℃の時にはステップ６０３の処理を実行した後にこのルーチンを終了し、機関の水温＜Ｈ℃の時にはステップ１００３の処理を実行した後にこのルーチンを終了する。
【００６７】
ステップ６０３は第２の実施例の処理と同じであり、吸気弁９の開弁進角量を、ＥＣＵ２１のＲＯＭ５２に記憶された重質燃料の進角マップＣから読み込む。マップＣは図７（ｃ） で説明したように、機関回転数と機関負荷の大きさに応じた吸気弁９の開弁進角特性を与えるものである。一方、ステップ１００３では、吸気弁９の開弁進角量を、ＥＣＵ２１のＲＯＭ５２に記憶された重質燃料の進角マップＦから読み込む。マップＦは機関水温が低い時の重質燃料用の進角マップであり、その特性は図１１（ｃ） に実線で示される。マップＦもマップＣと同様に、機関回転数と機関負荷の大きさに応じた吸気弁９の開弁進角特性を与えるものであるが、図７（ｃ） に示されるマップＣと比べると分かるように、機関回転数と機関負荷の大きさに応じた吸気弁９の開弁進角値は、機関水温が高い時に比べて小さくなっている。なお、比較のために、マップＦには軽質燃料の機関低温時の開弁進角特性を点線で示してある。
【００６８】
第５の実施例は、図１０で説明した手順から分かるように、第２の実施例で説明した手順に機関水温の判定が加わったものである。即ち、第５の実施例は、第２の実施例における燃料の性状に応じた吸気弁９の開弁進角値を、機関水温が低い時には、水温に応じた別の進角マップによって小さくしている点が、第２の実施例と異なっている。そして、燃料に重質燃料や中質燃料が使用された場合には、吸気弁９に小さな開弁進角値を与えることを決定する水温値が、軽質燃料よりも中質燃料の方が高く、また、中質燃料よりも重質燃料の方が高くされている。この結果、吸気弁９の開弁進角値が機関の水温と燃料性状に応じてきめ細かく制御されることになり、一層確実にドライバビリティの悪化が防止されると共に、燃費が向上し、排気エミッションの最適化が図れる。
【００６９】
なお、第５、第６の実施例では機関の水温の代わりに、機関の油温を検出して使用しても良い。また、機関の水温と油温とを併用してよりきめ細かく制御しても良い。また、以上の実施例では、燃料性状の判定をベーパ流量計４４の出力によってＥＣＵ２１が判定していたが、燃料性状の判定は、燃料タンク１７に燃料センサを取りつけて行っても良いものである。
【００７０】
また、以上説明した実施例では、第１の実施例のみにおいてバルブ開閉特性制御装置の排気弁の閉弁時期の遅角制御について説明を行ったが、第２から第５の実施例においてもバルブ開閉特性制御装置の排気弁の閉弁時期の遅角制御については吸気弁の開弁時期の進角制御と同様に行うことができる。
【００７１】
【発明の効果】
請求項１に記載の発明によれば、燃料性状に応じて、バルブ可変手段の作動量を制御する制御手段の作動速度が変更されるため、燃料の壁面付着量の変化量を制御することが可能となり、燃焼を安定させることができる効果を奏する。
【００７２】
請求項２に記載の発明によれば、燃料の壁面付着量が機関温度により変ることを考慮した制御が行われるため、制御が最適化される効果を奏する。
【図面の簡単な説明】
【図１】本発明のバルブ開閉特性制御装置を備えた電子燃料噴射制御式の多気筒内燃機関の全体構成を示す構成図である。
【図２】図１のＥＣＵの内部構成とセンサとの接続関係を示す回路図である。
【図３】（ａ） は本発明の内燃機関のバルブ開閉特性制御装置における燃料性状検知手順を示すフローチャート、（ｂ） は（ａ） において求められた燃料性状判定係数と燃料性状との関係を示す特性図である。
【図４】本発明の内燃機関のバルブ開閉特性制御装置の吸気弁の制御手順の第１の実施例を示すフローチャートである。
【図５】本発明の内燃機関のバルブ開閉特性制御装置の排気弁の制御手順の第１の実施例を示すフローチャートである。
【図６】・ 本発明の内燃機関のバルブ開閉特性制御装置の吸気弁の制御手順の第２の実施例を示すフローチャートである。
【図７】（ａ） は図６の制御手順における軽質燃料の進角マップの特性図、（ｂ） は図６の制御手順における中質燃料の進角マップの特性図、（ｃ） は図６の制御手順における重質燃料の進角マップの特性図である。
【図８】本発明の内燃機関のバルブ開閉特性制御装置の吸気弁の制御手順の第３の実施例を示すフローチャートである。
【図９】本発明の内燃機関のバルブ開閉特性制御装置の吸気弁の制御手順の第４の実施例を示すフローチャートである。
【図１０】本発明の内燃機関のバルブ開閉特性制御装置の吸気弁の制御手順の第５の実施例を示すフローチャートである。
【図１１】（ａ） は図６の制御手順における軽質燃料の機関水温が低い時の進角マップの特性図、（ｂ） は図６の制御手順における中質燃料の機関水温が低い時の進角マップの特性図、（ｃ） は図６の制御手順における重質燃料の機関水温が低い時の進角マップの特性図である。
【図１２】（ａ） はバルブオーバラップを得るために吸気弁を進角させた時の特性を示す吸気弁と排気弁の開弁特性図、（ｂ） はバルブオーバラップを得るために排気弁を遅角させた時の特性を示す吸気弁と排気弁の開弁特性図である。
【符号の説明】
８…排気弁
９…吸気弁
１０…バルブ開閉特性制御装置
１１…内燃機関
１７…燃料タンク
１８…加圧燃料
１９…燃料噴射弁
２１…ＥＣＵ
３８…回転角センサ
３９…水温センサ
４３…ベーパ通路
４４…ベーパ流量計
４５…キャニスタ
４６…回転部
４７…ベーパ流量センサ
４８…パージ通路
４９…パージコントロール弁[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve opening / closing characteristic control device for an internal combustion engine, and in particular, even when fuel having different properties is supplied, by correcting the valve opening / closing characteristics, the exhaust emission can be reduced without deteriorating the fuel consumption of the internal combustion engine. The present invention relates to a valve opening / closing characteristic control device for an internal combustion engine that can be reduced.
[0002]
[Prior art]
Conventionally, the opening and closing timings of the intake valve and exhaust valve provided in the cylinder head of the internal combustion engine are uniquely synchronized with the rotational phase of the crankshaft, so the intake and exhaust amount in the combustion chamber is provided in the intake passage. It depends on the opening of the throttle valve and the rotational speed of the engine.
[0003]
On the other hand, in recent years, a device (variable) that can change the opening and closing timings of an intake valve and an exhaust valve (hereinafter referred to as an intake / exhaust valve) in order to make it possible to adjust the intake / exhaust amount in the combustion chamber with more flexibility. A valve timing mechanism (VVT) has been put into practical use. The variable valve timing mechanism includes a mechanical variable mechanism that can change the opening / closing timing of the intake / exhaust valve and a control device that uses a computer to control the movement of the variable mechanism. The control device controls the opening / closing timing of at least one of the intake valve and the exhaust valve by controlling the variable mechanism in accordance with the operating state of the engine. Control the amount of lap). By this control, the amount of air sucked into the combustion chamber or the amount of exhaust gas once exhausted from the combustion chamber flows back into the combustion chamber and remains, that is, the internal EGR amount, is optimized, and the engine output and emission In addition, fuel economy and the like are improved.
[0004]
Some variable valve timing mechanisms include a variable mechanism that can continuously change the opening and closing timing of the intake and exhaust valves. In such a continuously variable variable valve timing mechanism, the engine operating state is detected by a computer to calculate the target opening / closing timing of the intake / exhaust valve, and the actual opening / closing timing of the intake / exhaust valve is detected. The variable mechanism is feedback controlled so as to match.
[0005]
On the other hand, in such a continuously variable type variable valve timing mechanism, when an abnormality occurs in which the desired operation cannot be obtained in the variable mechanism, various problems occur in the engine. For example, if the variable mechanism does not operate when the valve load is large when the engine load is small, the engine may stall. And once a stall occurs, the abnormality of the variable mechanism cannot be detected thereafter.
[0006]
Therefore, in the continuously variable variable valve timing mechanism, by detecting the abnormality of the control device with the occurrence of the engine stall as a determination condition, the abnormality of the variable mechanism can be detected even after the engine stops due to the stall. The present applicant has already proposed an abnormality detection device for a valve timing control device of an internal combustion engine (see Japanese Patent Application Laid-Open No. 9-60535).
[0007]
The continuously variable type variable valve timing mechanism described in Japanese Patent Laid-Open No. 9-60535 has an effect of reducing NOx due to an increase in internal EGR when the valve overlap amount is increased, and an effect of improving fuel consumption due to pumping loss is obtained. Is disclosed.
By the way, the components of the fuel used in the internal combustion engine are not constant regardless of the use conditions, and how many types of volatilities become the same according to the temperature of the place where the fuel is mainly used. It is divided into the characteristics. Such fuel properties are roughly classified into the following three types.
[0008]
Light fuel: Fuel with many low boiling points
Heavy fuel: Low boiling point fuel
Medium fuel: Fuel with low boiling point between light fuel and heavy fuel
[0009]
[Problems to be solved by the invention]
However, in the continuously variable type variable valve timing mechanism described in Japanese Patent Laid-Open No. 9-60535, the fuel property as described above is not taken into consideration, and control according to the fuel property is not performed. When heavy fuel is used, the amount of fuel adhering to the wall increases, and the amount of adhering fuel is unstable, so that combustion may become unstable.
[0010]
Therefore, the present invention has a NOx reduction effect regardless of the fuel property by controlling the valve overlap amount in consideration of the fuel property in the continuously variable variable valve timing mechanism, and the fuel consumption due to the pumping loss. It is an object of the present invention to provide a valve opening / closing characteristic control device for an internal combustion engine that can achieve the above improvement effect.
[0011]
[Means for Solving the Problems]
According to the first aspect of the present invention, the valve variable means capable of changing the valve overlap amount from the opening of the intake valve of one cylinder to the closing of the exhaust valve is provided, and this is changed according to the operating state of the engine. In a valve opening / closing characteristic control apparatus for an internal combustion engine having a control means for controlling an operation amount of a valve variable means, a fuel property detection means for detecting a property of fuel burned in the internal combustion engine, and a fuel property detection means detected by the fuel property detection means There is provided a valve opening / closing characteristic control device for an internal combustion engine, characterized in that an operation speed correction means of a control means for correcting the control speed of the control means is provided according to fuel properties.
[0012]
According to the invention described in claim 2, in claim 1The valve opening / closing characteristic control device for an internal combustion engine according to claim 1, wherein the control means operates the valve variable means when the engine temperature is equal to or higher than a predetermined value. .
[0013]
That is, in the invention of claim 1, since the operating speed of the control means for controlling the operating amount of the valve variable means is changed according to the fuel property, it becomes possible to control the amount of change in the fuel wall surface adhering amount, Combustion can be stabilized.
[0014]
That is, in the invention of claim 2, since the valve variable means is operated in consideration of the fact that the amount of fuel wall surface adhesion varies with the engine temperature, further optimal control can be achieved.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail based on specific examples with reference to the accompanying drawings.
FIG. 1 shows the overall configuration of an electronic fuel injection control type multi-cylinder internal combustion engine 11 equipped with a valve opening / closing characteristic control device 10 of the present invention. The internal combustion engine 11 is a 4-cylinder 4-cycle spark ignition internal combustion engine, and is controlled by an ECU (engine control unit) 21 incorporating a microcomputer.
[0017]
A throttle valve 12 and a surge tank 23 are provided in this order on the downstream side of the air cleaner 22. An intake air temperature sensor 24 that detects the intake air temperature is attached in the vicinity of the air cleaner 22, and an idle switch 25 that is turned on when the throttle valve 12 is fully closed is attached to the throttle valve 12. Further, the surge tank 23 is provided with a diaphragm type pressure sensor 26. On the other hand, a bypass passage 13 that bypasses the throttle valve 12 and connects the upstream side and the downstream side of the throttle valve 12 is provided, and an ISCV whose opening degree is controlled by a solenoid in the middle of the bypass passage 13. (Idle speed control valve) 14 is provided. The current flowing through the ISCV 14 is duty controlled to adjust the opening of the ISCV 14, and as a result, the amount of air flowing through the bypass passage 13 is adjusted to control the idling rotational speed to the target rotational speed.
[0018]
The surge tank 23 communicates with the combustion chamber 30 of the engine 11 through the intake manifold 27 and the intake port 28. A fuel injection valve 19 is provided on the downstream side of the surge tank 23 for supplying pressurized fuel 18 corresponding to the amount of intake air detected by the pressure sensor 26 from the fuel supply system to the intake port for each cylinder. ing. The output of the idle switch 25 and the output of the pressure sensor 26 are input to the ECU 21.
[0019]
The exhaust gas discharged from the combustion chamber 30 is guided to the catalyst device 33 through the exhaust port 31 and the exhaust manifold 32, purified, and discharged into the atmosphere. The exhaust manifold 32 on the upstream side of the catalyst device 33 is provided with an oxygen sensor 41 which is a kind of air-fuel ratio sensor. The oxygen sensor 41 generates an electrical signal according to the oxygen component concentration in the exhaust gas. The output of the oxygen sensor 41 is input to the ECU 21.
[0020]
The intake port 28 is opened and closed by the intake valve 9, and the exhaust port 31 is opened and closed by the exhaust valve 8. The opening / closing timing of the exhaust valve 8 and the intake valve 9 is controlled by the valve opening / closing characteristic control device 10. The valve opening / closing characteristic control apparatus 10 according to this embodiment can perform the delay control of the closing timing of the exhaust valve 8 and the advance control of the opening timing of the intake valve 9. The period (valve overlap amount) during which the valve 9 is open and both are simultaneously open can be controlled. The valve opening / closing characteristic control device 10 is controlled by the ECU 21. Since the configuration of the valve opening / closing characteristic control device 10 is the same as that described in Japanese Patent Application Laid-Open No. 9-60535 filed by the present applicant, the description thereof is omitted here.
[0021]
Reference numeral 34 denotes an ignition plug for generating a spark in the combustion chamber 30, and reference numeral 35 denotes a piston that reciprocates in the combustion chamber 30. The igniter 36 generates a high voltage, and this high voltage is distributed and supplied to the spark plug 34 of each cylinder by the distributor 37. The rotation angle sensor 38 detects the rotation of the rotation shaft of the distributor 37. For example, an engine rotation signal is sent from the rotation angle sensor 38 to the ECU 21 every 30 ° CA.
[0022]
A water temperature sensor 39 for detecting the temperature of the cooling water is provided in the cylinder block 40 of the internal combustion engine 11. The water temperature sensor 39 generates an analog voltage electrical signal corresponding to the temperature of the cooling water, and a water temperature sensor signal (THW) is sent to the ECU 21.
A fuel temperature sensor 42 is provided at the lower part of the fuel tank 17, whereby the temperature of the fuel 18 is measured. A vapor passage 43 is formed in the upper portion of the fuel tank 17, and the vapor passage 43 communicates with a canister 45 through a vapor flow meter 44. The vapor generated in the fuel tank 17 is measured by the vapor flow meter 44 and then flows into the canister 45. The vapor flow meter 44 includes a rotating unit 46 that rotates in response to the vapor flow rate. The rotation of the rotating unit 46 is detected by a vapor flow sensor 47, and a detected signal of the detected vapor flow rate is input to the ECU 21. The
[0023]
Based on the vapor flow rate detection signal detected by the vapor flow rate sensor 47, the ECU 21 determines the property of the fuel 18 in the fuel tank 17, that is, the fuel, depending on the difficulty of evaporation of the fuel 18 in the fuel tank 17 (distillation characteristics). Can be detected as light fuel, heavy fuel, or medium fuel.
The vapor adsorbed on the canister 45 is sucked into the intake manifold 27 through the purge passage 48. Since the purge passage 48 is provided with an orifice (not shown), the negative pressure of the intake manifold 27 is not directly applied to the fuel tank 17. A purge control valve 49 is provided in the middle of the purge passage 48, and the opening of the purge control valve 49 is adjusted by adjusting the current flowing through the solenoid of the purge control valve 49, and the purge flowing through the purge passage 48 is adjusted. The flow rate is adjusted.
[0024]
The ECU 21 incorporating the microcomputer has a configuration as shown in FIG. In the figure, the same components as those in FIG. In FIG. 2, an ECU 21 includes an MPU (micro processor unit) 51, a ROM 52 incorporating a processing program, a RAM 53 used as a work area, a backup RAM 54 that retains data even after the engine is stopped, and a clock that supplies a clock signal to the MPU 51. A generator 55 is provided, which are connected to each other by a bidirectional bus line 56. An input / output port 57, an input port 57, and an output port 59 are connected to the bus line 56.
[0025]
Four buffers 64 to 67 are connected to the input / output port 57 via a multiplexer 68 and an A / D converter 69. A detection signal from the pressure sensor 26 is input to the buffer 64 via the filter 63, but detection signals from the intake air temperature sensor 24, the water temperature sensor 65, and the fuel temperature sensor 42 are input to the buffers 65 to 67, respectively. . The filter 63 removes a vibration component of the intake pipe pressure included in the detection signal of the pressure sensor 26. The multiplexer 68 selects and outputs the input signal.
[0026]
A detection signal of the oxygen sensor 41 is input to the input port 58 via the buffer 70 and the comparator 71, and detection outputs of the rotation angle sensor 38 and the vapor flow sensor 47 are input via the waveform shaping circuit 72. Further, an ON / OFF signal from the idle signal 25 is also input to the input port 58.
Drive circuits 73 to 77 are connected to the output port 59, respectively. The drive circuit 73 drives the igniter 36, the drive circuit 74 drives the fuel injection valve 19, the drive circuit 75 drives the ISCV 14, the drive circuit 76 drives the purge control valve 49, and the drive circuit 77 has valve opening / closing characteristics. The control device 10 is driven.
[0027]
The ECU 21 configured as described above can detect the property of the fuel 18 by the vapor flow sensor 47. An example of the detection will be described with reference to the flowchart shown in FIG.
FIG. 3A shows a calculation procedure of the fuel property determination coefficient NVA10T, which is a part of the main routine. In step 301, the flow meter measurement time CVA is counted up by a 4 ms routine (not shown), and it is determined whether or not a predetermined value, for example, 10 seconds or more is reached. If so, go to the next Step 302. In step 302, the measurement time CVA of the flow meter is reset to zero. Accordingly, steps 302 to 306 are executed once every 10 seconds.
[0028]
On the other hand, the ECU 21 counts up in an external interrupt routine that is activated only when the detection signal of the vapor flow sensor 47 described above changes from a low voltage to a high voltage, that is, every time the rotating unit 46 of FIG. A vapor flow counter. Then, the count value NVA of the vapor amount counter is set to the variable NVA10 in step 303 following step 302. The count value NVA of the vapor amount counter is reset to 0 in the next step 304. Therefore, the value of the variable NVA10 indicates the number of rotations of the rotating portion 46 of the vapor flow meter 44 per 10 seconds, and indicates a value proportional to the vapor flow rate.
[0029]
In the following step 305, the temperature of the fuel 18 is detected by the fuel temperature sensor 42, and the fuel temperature correction coefficient KVA is calculated using the function f (THF) based on the obtained fuel temperature detection signal THF. That is, even when the fuel has the same distillation characteristics, the amount of vapor generated is lower when the fuel temperature is low than when the fuel temperature is high. For this reason, in order to correct the difference in the amount of vapor generated due to the fuel temperature, the fuel temperature correction coefficient KVA is set to increase as the fuel temperature decreases.
[0030]
In the next step 306, the fuel property correction coefficient NVA10T is obtained by an arithmetic expression of NVA10 × KVA. That is, the fuel property correction coefficient NVA10T is a value obtained by correcting the vapor flow rate for 10 seconds with the fuel temperature correction coefficient. When this value is small, it can be seen that the fuel is heavy fuel with a high high boiling point content (low low boiling point content). FIG. 3B shows the relationship between the value of the fuel property correction coefficient NVA10T and the fuel property.
[0031]
In step 307, it is determined whether or not the value of the fuel property correction coefficient NVA10T is equal to or greater than a predetermined value α. . On the other hand, if NVA10T <α in step 307, the process proceeds to step 309, in which it is determined whether the value of the fuel property correction coefficient NVA10T is equal to or smaller than a predetermined value β that is smaller than the predetermined value α. If NVA10T ≦ β in step 309, the process proceeds to step 311 to determine that the fuel is heavy fuel, and this routine is terminated. On the other hand, if NVA10T> β in step 309, the process proceeds to step 311 to determine that the fuel is a medium fuel and this routine is terminated.
[0032]
In the case of an internal combustion engine equipped with a continuously variable variable valve timing mechanism, this fuel property is determined while the variable valve timing mechanism is not operated, as in the cold start, and the detected fuel property is stored in the RAM 53. Alternatively, it may be stored in the backup RAM 54. On the other hand, in this embodiment, since the unit measurement time of the vapor flow rate is 10 seconds, the fuel property can be detected sequentially even while the vehicle is traveling, and the vehicle refuels in the middle of traveling and has different properties. Even when fuel is supplied, a change in fuel properties can be detected.
[0033]
Here, the advance variable control of the opening timing of the intake valve and the exhaust valve of the continuously variable variable valve timing mechanism provided in the internal combustion engine that can determine the property of the fuel by the procedure as described above. The retard angle control of the valve closing timing will be described.
FIG. 4 is a flowchart showing a first embodiment of the procedure for controlling the advance of the opening timing of the intake valve 9 in the valve opening / closing characteristic control apparatus 10 of the internal combustion engine. In step 400, the fuel properties obtained by the procedure described in FIG. 3A are read. In subsequent step 401, it is determined whether or not the fuel is light.
[0034]
When the fuel is light fuel, the routine proceeds to step 402, where it is determined whether or not the intake valve 9 is in the valve opening advance condition. When the intake valve 9 is not in the valve opening advance condition, the routine is terminated as it is. However, if the intake valve 9 is in the valve opening advance condition, the routine proceeds to step 403 and the valve opening advance control amount of the intake valve 9 is set to X. Set this to CA and exit this routine. On the other hand, if it is determined in step 401 that the fuel is not light, the process proceeds to step 404 to determine whether or not the fuel is heavy.
[0035]
If the fuel is not a heavy fuel, since the fuel is a medium fuel, the routine proceeds to step 405, where it is determined whether the intake valve 9 is in a valve opening advance condition. If the intake valve 9 is not in the valve opening advance condition, the routine is terminated. If the intake valve 9 is in the valve opening advance condition, the routine proceeds to step 403, where the valve opening advance control amount of the intake valve 9 is set to Y. Set this to CA and exit this routine. The valve opening advance control amount Y ° CA of the intake valve 9 set at this time is smaller than the valve opening advance control amount X ° CA when the fuel is light. On the other hand, if it is determined in step 404 that the fuel is heavy, the process proceeds to step 407.
[0036]
If the fuel is heavy fuel, it is determined in step 407 whether the intake valve 9 is in a valve opening advance condition. When the intake valve 9 is not in the valve opening advance condition, the routine is terminated as it is. However, if the intake valve 9 is in the valve opening advance condition, the routine proceeds to step 408 and the valve opening advance control amount of the intake valve 9 is set to Z. Set this to CA and exit this routine. The valve opening advance control amount Z ° CA of the intake valve 9 set when the fuel is heavy fuel is smaller than the valve opening advance control amount Y ° CA when the fuel is medium.
[0037]
Here, the valve overlap which is the overlap of the valve opening periods of the exhaust valve 8 and the intake valve 9 of a certain cylinder in the intake stroke of the internal combustion engine will be described with reference to FIG. In FIG. 12A, the characteristic indicated by the solid line EV is the valve opening characteristic of the exhaust valve 8, and the characteristic indicated by the solid line IV is the valve opening characteristic of the intake valve 9. In this case, the exhaust valve 8 and the intake valve 9 The valve opening periods do not overlap, and the valve overlap amount is zero. When the valve opening advancement condition of the intake valve 9 is advanced from this state, the opening timing of the intake valve 9 is advanced as shown by the broken line in FIG. The valve opening characteristic of the exhaust valve 8 and the valve opening characteristic of the intake valve 9 overlap. The overlap of the valve opening characteristic of the exhaust valve 8 and the valve opening characteristic of the intake valve 9 is the valve overlap amount. The overlap amount increases as the valve opening advance control amount of the intake valve 9 increases.
[0038]
In the conventional valve opening / closing characteristic control device, the valve opening advance control amount of the intake valve 9 is changed in accordance with the operating state of the engine. However, the control amount is not dependent on the fuel property, and in a certain operating state of the engine. It was constant. Generally, in an internal combustion engine equipped with a valve opening / closing characteristic control device, increasing the valve overlap amount increases the internal EGR amount. For this reason, when heavy fuel with a large amount of wall surface adhesion is used, combustion becomes unstable and drivability deteriorates.
[0039]
In order to prevent this, in the first embodiment described above, when a heavy fuel or a medium fuel is used as the fuel according to the procedure described with reference to FIG. The amount is smaller than when light fuel is used as the fuel. As a result, in the case of the valve opening advance condition of the intake valve 9, the valve overlap amount is changed according to the properties of the fuel, so that deterioration of drivability is prevented.
[0040]
FIG. 5 is a flowchart showing a first embodiment of a procedure for retarding the closing timing of the exhaust valve 8 of the valve opening / closing characteristic control apparatus 10 for an internal combustion engine. In the description of the control procedure of the closing timing of the exhaust valve 8, the same procedure as the control procedure of the opening timing of the intake valve 9 described in FIG.
Also in the retard control of the closing timing of the exhaust valve 8, the procedures of steps 400, 401, and 404 for determining the properties of the fuel are the same. If it is determined in step 401 that the fuel is light fuel, the process proceeds to step 501, and it is determined whether or not the exhaust valve 8 is in a valve closing delay condition. When the exhaust valve 8 is not closed, the routine is terminated as it is. However, when the exhaust valve 8 is closed, the routine proceeds to step 502, where the control amount of the exhaust valve 8 is set to P. Set this to CA and exit this routine.
[0041]
On the other hand, if it is determined in step 404 that the fuel is a medium fuel, the process proceeds to step 503, where it is determined whether the exhaust valve 8 is in a valve closing delay condition. When the exhaust valve 8 is not in the valve closing delay condition, the routine is terminated as it is. However, when the exhaust valve 8 is in the valve closing delay condition, the routine proceeds to step 504 and the valve closing delay control amount of the exhaust valve 8 is set to Q. Set this to CA and exit this routine. The valve closing delay control amount Q ° CA of the exhaust valve 8 set at this time is smaller than the valve closing delay control amount P ° CA when the fuel is light.
[0042]
On the other hand, if it is determined in step 404 that the fuel is heavy, the process proceeds to step 505. In step 505, it is determined whether or not the exhaust valve 8 is in a valve closing delay condition. When the exhaust valve 8 is not closed, the routine is terminated as it is. However, when the exhaust valve 8 is closed, the routine proceeds to step 506, and the valve closing delay control amount of the exhaust valve 8 is set to R. Set to CA and exit this routine. The valve closing delay control amount R ° CA of the intake valve 9 set when the fuel is heavy fuel is smaller than the valve closing delay control amount Q ° CA when the fuel is medium.
[0043]
Thus, in the first embodiment, the valve closing delay control amount of the exhaust valve 8 is also adjusted according to the properties of the fuel. This will be described with reference to FIG. 12B. In FIG. 12B as well, the characteristic indicated by the solid line EV is the valve opening characteristic of the exhaust valve 8, and the characteristic indicated by the solid line IV is the opening characteristic of the intake valve 9. It is a valve characteristic. For the exhaust valve 8 as well, if the closing of the exhaust valve 8 is delayed, the opening characteristic of the exhaust valve 8 becomes as shown by a broken line in FIG. 12B, and the valve overlap amount between the exhaust valve 8 and the intake valve 9 is reduced. growing.
[0044]
In the first embodiment, according to the procedure described with reference to FIG. 5, even when the exhaust valve 8 is closed, if heavy fuel or medium fuel is used as the fuel, the exhaust valve 8 is closed. The valve retard control amount is made smaller than when light fuel is used as the fuel. As a result, in the case of the valve closing delay condition of the exhaust valve 8, the valve overlap amount is changed so as to become smaller as the fuel becomes heavier under the same valve opening angle condition according to the nature of the fuel. It will prevent the drivability from deteriorating.
[0045]
As described above, the valve opening advance control amount of the intake valve 9 and the valve closing retard control amount of the exhaust valve 8 can be changed according to the fuel properties by substantially the same control. Therefore, in the following description, only the embodiment of the valve opening advance angle control of the intake valve 9 in consideration of the properties of the fuel will be described, and the description of the embodiment of the valve closing delay angle control of the exhaust valve 8 will be omitted.
FIG. 6 is a flowchart showing a second embodiment of the procedure for controlling the advance of the opening timing of the intake valve 9 in the valve opening / closing characteristic control apparatus 10 of the internal combustion engine. In the description of the control procedure of the second embodiment, the same procedure as the control procedure of the valve opening timing of the intake valve 9 of the first embodiment described with reference to FIG.
[0046]
In step 600, the fuel properties obtained by the procedure described with reference to FIG. 3A are read, and the engine load and the rotational speed are read. In subsequent steps 401 and 404, it is determined whether the fuel property is light fuel, medium fuel, or heavy fuel.
If the fuel is light fuel, it is determined in step 402 whether the intake valve 9 is in a valve opening advance condition. When the intake valve 9 is not in the valve opening advance condition, the routine is terminated as it is. However, when the intake valve 9 is in the valve opening advance condition, the routine proceeds to step 601. In step 601, the advance angle map A of the soft fuel stored in the ROM 52 of the ECU 21 is read for the valve opening advance amount of the intake valve 9, and this routine is terminated. As shown in FIG. 7A, the map A gives the valve opening advance characteristic of the intake valve 9 in accordance with the engine speed and the engine load.
[0047]
If the fuel is a medium fuel, it is determined in step 405 whether the intake valve 9 is in a valve opening advance condition. Then, when the intake valve 9 is not in the valve opening advance condition, the routine is terminated as it is. In step 602, the valve opening advance amount of the intake valve 9 is read from the advance map B of medium fuel stored in the ROM 52 of the ECU 21, and this routine is terminated. The map B has a characteristic indicated by a solid line in FIG. 7B, and gives a valve opening advance characteristic of the intake valve 9 in accordance with the engine speed and the engine load. For comparison, in map B, the valve opening advance characteristic of light fuel is indicated by a dotted line, and the valve opening advance characteristic of heavy fuel is indicated by a two-dot chain line.
[0048]
Further, if the fuel is heavy fuel, it is determined in step 407 whether or not the intake valve 9 is in a valve opening advance condition. Then, when the intake valve 9 is not in the valve opening advance condition, the routine is terminated as it is. In step 603, the valve opening advance amount of the intake valve 9 is read from the advance map C of the heavy fuel stored in the ROM 52 of the ECU 21, and this routine is terminated. The map C has a characteristic indicated by a solid line in FIG. 7C, and gives a valve opening advance characteristic of the intake valve 9 in accordance with the engine speed and the engine load. For comparison, map C shows the valve opening advance characteristic of light fuel by a dotted line.
[0049]
In the second embodiment, when heavy fuel or medium fuel is used as the fuel according to the procedure described in FIG. 6, the engine speed and the engine load that give the same valve opening advance value of the intake valve 9 are used. The value of has increased. As a result, in the case of the valve opening advance condition of the intake valve 9, the valve overlap amount is changed so as to become smaller as the fuel becomes heavier under the same valve opening angle condition according to the nature of the fuel. It will prevent the drivability from deteriorating.
[0050]
FIG. 8 is a flowchart showing a third embodiment of the procedure for controlling the advance of the opening timing of the intake valve 9 in the valve opening / closing characteristic control apparatus 10 of the internal combustion engine. In the description of the control procedure of the third embodiment, the same procedure as the control procedure of the valve opening timing of the intake valve 9 of the first embodiment described with reference to FIG.
In step 400, the fuel properties obtained by the procedure described in FIG. 3A are read. In subsequent steps 401 and 404, it is determined whether the fuel property is light fuel, medium fuel, or heavy fuel.
[0051]
If the fuel is light fuel, it is determined in step 402 whether the intake valve 9 is in a valve opening advance condition. When the intake valve 9 is not in the valve opening advance condition, the routine is terminated as it is. However, when the intake valve 9 is in the valve opening advance condition, the routine proceeds to step 801. In step 801, the valve opening angular velocity of the intake valve 9 is set to Fdeg / ms, and this routine is terminated.
[0052]
If the fuel is a medium fuel, it is determined in step 405 whether the intake valve 9 is in a valve opening advance condition. When the intake valve 9 is not in the valve opening advance condition, the routine is terminated as it is. In step 802, the valve opening advance speed of the intake valve 9 is set to Mdeg / ms, and this routine is terminated. The valve opening advance speed Mdeg / ms at this time is a value smaller than the valve opening advance speed Fdeg / ms of the intake valve 9 when the fuel is light fuel.
[0053]
Further, if the fuel is heavy fuel, it is determined in step 407 whether or not the intake valve 9 is in a valve opening advance condition. When the intake valve 9 is not in the valve opening advance condition, the routine is terminated as it is. However, when the intake valve 9 is in the valve opening advance condition, the routine proceeds to step 803. In step 803, the valve opening advance speed of the intake valve 9 is set to Sdeg / ms, and this routine ends. The valve opening advance speed Sdeg / ms at this time is a value smaller than the valve opening advance speed Mdeg / ms of the intake valve 9 when the fuel is medium fuel.
[0054]
The control of the advance speed of the intake valve 9 in the valve opening / closing characteristic control device 10 is performed by duty-controlling the oil pressure applied to the advance chamber and the retard chamber provided in the valve opening / closing property control device 10. It can be carried out. That is, if the duty ratio is increased and the hydraulic pressure applied to the advance chamber is increased, the advance speed can be increased.
[0055]
In the third embodiment, when heavy fuel or medium fuel is used as the fuel according to the procedure described with reference to FIG. 8, the same valve opening advance speed of the intake valve 9 is higher than that of light fuel. The heavy fuel is smaller than the medium fuel. As a result, in the case of the valve opening advance condition of the intake valve 9, the valve overlap amount is changed so as to become smaller as the fuel becomes heavier under the same valve opening angle condition according to the nature of the fuel. It will prevent the drivability from deteriorating.
[0056]
FIG. 9 is a flowchart showing a fourth embodiment of the procedure for controlling the advance of the valve opening timing of the intake valve 9 in the valve opening / closing characteristic control apparatus 10 of the internal combustion engine. In the description of the control procedure of the fourth embodiment, the same procedure as the control procedure of the valve opening timing of the intake valve 9 of the first embodiment described with reference to FIG.
In step 900, the fuel properties obtained by the procedure described in FIG. 3A and the engine water temperature are read. In subsequent steps 401 and 404, it is determined whether the fuel property is light fuel, medium fuel, or heavy fuel.
[0057]
If the fuel is light fuel, it is determined in step 402 whether the intake valve 9 is in a valve opening advance condition. When the intake valve 9 is not in the valve opening advance condition, the routine is terminated as it is. However, when the intake valve 9 is in the valve opening advance condition, the routine proceeds to step 901. In step 901, it is determined whether the water temperature of the engine is equal to or higher than L ° C. When the engine water temperature <L ° C., this routine is terminated as it is, but when the engine water temperature ≧ L ° C., the routine proceeds to step 902. In step 902, the valve opening advance control of the intake valve corresponding to the soft fuel is executed, and this routine is terminated. The intake valve opening advance angle control according to the soft fuel is performed by the advance angle control amount X described in the first embodiment, the advance value by the advance map A described in the second embodiment, Any one of the advance speeds Fdeg / ms described in the third embodiment can be executed.
[0058]
If the fuel is a medium fuel, it is determined in step 405 whether the intake valve 9 is in a valve opening advance condition. When the intake valve 9 is not in the valve opening advance condition, the routine is terminated as it is. However, if the intake valve 9 is in the valve opening advance condition, the routine proceeds to step 903. In step 903, it is determined whether the water temperature of the engine is equal to or higher than I ° C. This engine water temperature I is higher than the engine water temperature L in step 901. When the engine water temperature <I ° C., this routine is terminated as it is, but when the engine water temperature ≧ I ° C., the routine proceeds to step 904. In step 904, the valve opening advance control of the intake valve corresponding to the medium fuel is executed, and this routine is finished. The valve opening advance control of the intake valve in accordance with the medium fuel is performed when the advance control in step 902 is the advance control amount X described in the first embodiment. When the advance value is based on the advance map A described in the above embodiment, the advance value is based on the advance map B, and when the advance speed is Fdeg / ms described in the third embodiment, the advance speed Mdeg / ms.
[0059]
Further, if the fuel is heavy fuel, it is determined in step 407 whether or not the intake valve 9 is in a valve opening advance condition. Then, when the intake valve 9 is not in the valve opening advance condition, this routine is terminated as it is. However, when the intake valve 9 is in the valve opening advance condition, the routine proceeds to step 905. In step 905, it is determined whether the engine water temperature is equal to or higher than H ° C. This engine water temperature H is lower than the engine water temperature I in step 903. When the engine water temperature <H ° C., the routine is terminated as it is, but when the engine water temperature ≧ H ° C., the routine proceeds to step 906. In step 906, the intake valve opening advance angle control corresponding to the heavy fuel is executed, and this routine is terminated. The intake valve opening advance control in accordance with the heavy fuel is performed when the advance control in step 902 is the advance control amount X described in the first embodiment. When the advance value is based on the advance map A described in the above embodiment, the advance value is based on the advance map C, and when the advance speed is Fdeg / ms described in the third embodiment, the advance speed Sdeg / ms.
[0060]
In the fourth embodiment, as can be seen from the procedure described with reference to FIG. 9, the determination of the engine water temperature is added to the procedures described in the first to third embodiments. When heavy fuel or medium fuel is used as the fuel, the water temperature value for determining whether or not to perform the valve opening advance of the intake valve 9 is higher for the medium fuel than for the light fuel. High and heavy fuel is higher than medium fuel. As a result, the warm-up state of the engine is added to the determination of the valve opening advance condition of the intake valve 9, which further reliably prevents deterioration of drivability, improves fuel consumption, and optimizes exhaust emissions. Can be planned.
[0061]
FIG. 10 is a flowchart showing a fifth embodiment of the procedure for controlling the advance of the opening timing of the intake valve 9 in the valve opening / closing characteristic control apparatus 10 of the internal combustion engine. In the description of the control procedure of the fifth embodiment, the same procedure as the control procedure of the valve opening timing of the intake valve 9 of the first embodiment described with reference to FIG.
In step 1000, the fuel properties obtained by the procedure described in FIG. 3A, the engine water temperature, the engine load, and the engine speed are read. In subsequent steps 401 and 404, it is determined whether the fuel property is light fuel, medium fuel, or heavy fuel.
[0062]
If the fuel is light fuel, it is determined in step 402 whether the intake valve 9 is in a valve opening advance condition. When the intake valve 9 is not in the valve opening advance condition, the routine is terminated as it is. However, when the intake valve 9 is in the valve opening advance condition, the routine proceeds to step 901. In step 901, it is determined whether the water temperature of the engine is equal to or higher than L ° C. Then, when the engine water temperature ≧ L ° C., the routine is terminated after executing the process of step 601, and when the engine water temperature <L ° C., the routine is terminated after executing the process of step 1001.
[0063]
Step 601 is the same as the processing in the second embodiment, and the valve opening advance amount of the intake valve 9 is read from the advance angle map A of the soft fuel stored in the ROM 52 of the ECU 21. As described with reference to FIG. 7A, the map A gives the valve opening advance characteristic of the intake valve 9 according to the engine speed and the engine load. On the other hand, in step 1001, the valve opening advance amount of the intake valve 9 is read from the advance map D of the soft fuel stored in the ROM 52 of the ECU 21. Map D is an advance map for soft fuel when the engine water temperature is low, and its characteristics are shown in FIG. The map D, like the map A, gives the valve opening advance characteristic of the intake valve 9 according to the engine speed and the load of the engine. Compared with the map A shown in FIG. As can be seen, the valve opening advance value of the intake valve 9 corresponding to the engine speed and the engine load is smaller than when the engine water temperature is high.
[0064]
If the fuel is a medium fuel, it is determined in step 405 whether the intake valve 9 is in a valve opening advance condition. When the intake valve 9 is not in the valve opening advance condition, the routine is terminated as it is. However, if the intake valve 9 is in the valve opening advance condition, the routine proceeds to step 903. In step 903, it is determined whether the water temperature of the engine is equal to or higher than I ° C. This engine water temperature I is higher than the engine water temperature L in step 901. When the engine water temperature ≧ I ° C., the routine ends after executing the process of step 602. When the engine water temperature <I ° C., the routine ends after executing the process of step 1002.
[0065]
Step 602 is the same as the processing in the second embodiment, and the valve opening advance amount of the intake valve 9 is read from the advance angle map B of the medium fuel stored in the ROM 52 of the ECU 21. As described with reference to FIG. 7B, the map B gives the valve opening advance characteristic of the intake valve 9 according to the engine speed and the engine load. On the other hand, in step 1002, the valve opening advance amount of the intake valve 9 is read from the advance map E of the medium fuel stored in the ROM 52 of the ECU 21. Map E is an advance map for medium fuel when the engine water temperature is low, and its characteristics are shown by a solid line in FIG. The map E, like the map B, gives the valve opening advance characteristic of the intake valve 9 according to the engine speed and the engine load, but compared with the map B shown in FIG. 7 (b). As can be seen, the valve opening advance value of the intake valve 9 corresponding to the engine speed and the engine load is smaller than when the engine water temperature is high. For comparison, Map E shows the opening angle characteristics of light fuel at low engine temperatures with dotted lines, and the heavy fuel valve opening angle characteristics at low engine temperatures with two-dot chain lines. is there.
[0066]
Further, if the fuel is heavy fuel, it is determined in step 407 whether or not the intake valve 9 is in a valve opening advance condition. Then, when the intake valve 9 is not in the valve opening advance condition, this routine is terminated as it is. However, when the intake valve 9 is in the valve opening advance condition, the routine proceeds to step 905. In step 905, it is determined whether the engine water temperature is equal to or higher than H ° C. This engine water temperature H is lower than the engine water temperature I in step 903. When the engine water temperature is equal to or higher than H ° C., the routine ends after executing the processing of Step 603. When the engine water temperature <H ° C., the routine ends after executing the processing of Step 1003.
[0067]
Step 603 is the same as the processing in the second embodiment, and the valve opening advance amount of the intake valve 9 is read from the advance angle map C of the heavy fuel stored in the ROM 52 of the ECU 21. As described with reference to FIG. 7C, the map C gives the valve opening advance characteristic of the intake valve 9 according to the engine speed and the engine load. On the other hand, at step 1003, the valve opening advance amount of the intake valve 9 is read from the advance map F of heavy fuel stored in the ROM 52 of the ECU 21. Map F is an advance map for heavy fuel when the engine water temperature is low, and its characteristics are shown by a solid line in FIG. The map F, like the map C, gives the valve opening advance characteristic of the intake valve 9 according to the engine speed and the magnitude of the engine load. Compared to the map C shown in FIG. As can be seen, the valve opening advance value of the intake valve 9 corresponding to the engine speed and the engine load is smaller than when the engine water temperature is high. For comparison, the map F shows the valve opening advance characteristics of light fuel when the engine is cold at a dotted line.
[0068]
In the fifth embodiment, as can be seen from the procedure described with reference to FIG. 10, the determination of the engine water temperature is added to the procedure described in the second embodiment. That is, in the fifth embodiment, when the engine water temperature is low, the valve opening advance value corresponding to the fuel properties in the second embodiment is reduced by another advance map corresponding to the water temperature. This is different from the second embodiment. When heavy fuel or medium fuel is used as the fuel, the water temperature value that determines to give a small valve opening advance value to the intake valve 9 is higher for the medium fuel than for the light fuel. Also, heavy fuel is higher than medium fuel. As a result, the valve opening advance value of the intake valve 9 is finely controlled according to the engine water temperature and the fuel properties, so that the deterioration of drivability is more reliably prevented, the fuel consumption is improved, and the exhaust emission is improved. Can be optimized.
[0069]
In the fifth and sixth embodiments, the oil temperature of the engine may be detected and used instead of the engine water temperature. Further, the engine water temperature and oil temperature may be used in combination for finer control. In the above embodiment, the ECU 21 determines the fuel property based on the output of the vapor flow meter 44. However, the fuel property may be determined by attaching a fuel sensor to the fuel tank 17. .
[0070]
Further, in the embodiment described above, the delay angle control of the closing timing of the exhaust valve of the valve opening / closing characteristic control device has been described only in the first embodiment, but in the second to fifth embodiments, the valve is also controlled. The delay control of the closing timing of the exhaust valve of the opening / closing characteristic control device can be performed in the same manner as the advance control of the opening timing of the intake valve.
[0071]
【The invention's effect】
According to the first aspect of the present invention, since the operating speed of the control means for controlling the operating amount of the valve variable means is changed according to the fuel property, the amount of change in the fuel wall surface adhesion amount can be controlled. It becomes possible, and the effect which can stabilize combustion is produced.
[0072]
According to the second aspect of the present invention, since control is performed in consideration that the amount of fuel wall surface adhesion varies depending on the engine temperature, there is an effect that the control is optimized.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an overall configuration of an electronic fuel injection control type multi-cylinder internal combustion engine equipped with a valve opening / closing characteristic control device of the present invention.
FIG. 2 is a circuit diagram showing a connection relationship between an internal configuration of the ECU of FIG. 1 and a sensor.
FIG. 3A is a flowchart showing a fuel property detection procedure in the valve opening / closing characteristic control apparatus for an internal combustion engine of the present invention, and FIG. 3B is a diagram showing the relationship between the fuel property determination coefficient obtained in (a) and the fuel property. FIG.
FIG. 4 is a flowchart showing a first embodiment of an intake valve control procedure of the valve opening / closing characteristic control apparatus for an internal combustion engine according to the present invention;
FIG. 5 is a flowchart showing a first embodiment of an exhaust valve control procedure of the valve opening / closing characteristic control apparatus for an internal combustion engine according to the present invention;
FIG. 6 is a flowchart showing a second embodiment of the control procedure of the intake valve of the valve opening / closing characteristic control device of the internal combustion engine of the present invention.
7A is a characteristic diagram of an advance map of light fuel in the control procedure of FIG. 6, FIG. 7B is a characteristic diagram of an advance map of medium fuel in the control procedure of FIG. 6, and FIG. FIG. 6 is a characteristic diagram of an advance map of heavy fuel in the control procedure of FIG.
FIG. 8 is a flowchart showing a third embodiment of an intake valve control procedure of the valve opening / closing characteristic control apparatus for an internal combustion engine according to the present invention;
FIG. 9 is a flowchart showing a fourth embodiment of an intake valve control procedure of the valve opening / closing characteristic control apparatus for an internal combustion engine according to the present invention;
FIG. 10 is a flowchart showing a fifth embodiment of the control procedure of the intake valve of the valve opening / closing characteristic control apparatus for an internal combustion engine of the present invention.
11A is a characteristic diagram of an advance angle map when the engine water temperature of light fuel is low in the control procedure of FIG. 6, and FIG. 11B is a graph of when the engine water temperature of medium fuel is low in the control procedure of FIG. (C) is a characteristic diagram of the advance angle map when the engine temperature of the heavy fuel in the control procedure of FIG. 6 is low.
12A is an opening characteristic diagram of an intake valve and an exhaust valve showing characteristics when the intake valve is advanced to obtain a valve overlap, and FIG. 12B is an exhaust characteristic for obtaining a valve overlap. It is a valve opening characteristic diagram of an intake valve and an exhaust valve showing characteristics when the valve is retarded.
[Explanation of symbols]
8 ... Exhaust valve
9 ... Intake valve
10 ... Valve open / close characteristic control device
11 ... Internal combustion engine
17 ... Fuel tank
18 ... Pressurized fuel
19 ... Fuel injection valve
21 ... ECU
38 ... Rotation angle sensor
39 ... Water temperature sensor
43 ... Vapor passage
44 ... Vapor flow meter
45 ... Canister
46 ... Rotating part
47 ... Vapor flow sensor
48 ... Purge passage
49 ... Purge control valve

Claims (2)

１つの気筒の吸気弁の開弁から排気弁の閉弁までのバルブオーバラップ量を変更可能なバルブ可変手段を備え、機関の運転状態に応じてこのバルブ可変手段の作動量を制御する制御手段を有する内燃機関のバルブ開閉特性制御装置において、
内燃機関で燃焼される燃料の性状を検出する燃料性状検出手段と、
この燃料性状検出手段によって検出された燃料性状に応じて、前記制御手段の制御速度を補正する制御手段の作動速度補正手段と、
を設けたことを特徴とする内燃機関のバルブ開閉特性制御装置。Control means for providing valve variable means capable of changing the valve overlap amount from opening of the intake valve of one cylinder to closing of the exhaust valve, and controlling the operation amount of the valve variable means in accordance with the operating state of the engine In the valve opening / closing characteristic control device of the internal combustion engine having
Fuel property detection means for detecting the property of fuel burned in the internal combustion engine;
According to the fuel property detected by the fuel property detection means, the operation speed correction means of the control means for correcting the control speed of the control means,
A valve opening / closing characteristic control apparatus for an internal combustion engine, characterized by comprising: 請求項１に記載の内燃機関のバルブ開閉特性制御装置において、
前記制御手段は、機関温度が所定値以上の時に、前記バルブ可変手段を作動させることを特徴とする内燃機関のバルブ開閉特性制御装置。The valve opening / closing characteristic control apparatus for an internal combustion engine according to claim 1 ,
The valve opening / closing characteristic control device for an internal combustion engine, wherein the control means operates the valve variable means when the engine temperature is equal to or higher than a predetermined value.
JP01896398A 1998-01-30 1998-01-30 Control device for valve opening / closing characteristics of internal combustion engine Expired - Fee Related JP3632424B2 (en)

Priority Applications (2)

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JP01896398A JP3632424B2 (en) 1998-01-30 1998-01-30 Control device for valve opening / closing characteristics of internal combustion engine
US09/225,744 US6109225A (en) 1998-01-30 1999-01-05 Valve timing control device for an internal combustion engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP01896398A JP3632424B2 (en) 1998-01-30 1998-01-30 Control device for valve opening / closing characteristics of internal combustion engine

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JP3632424B2 true JP3632424B2 (en) 2005-03-23

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